• Pediatric Infection and Vaccine
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• v.11 no.2
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• pp.202-207
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• 2004

Group A streptococcus, also known as Streptococcus pyogenes, is a common bacterial pathogens of the upper respiratory tract and skin infections in children, but this organism is a less common cause of pneumonia, pericarditis. However, pneumonia that is caused by Streptococcus pyogenes, may be rapidly progressive course with developing severe consequences. It may be focal but often is bilateral and diffuse involvement of lung. Empyema is commonly developed, and pleurocentesis often yields thin, watery fluid that continues to flow out when a chest tube is inserted. Antimicrobial resistance to the ${\beta}$-lactam antibiotics has not been reported against group A streptococci, whereas increasing resistance to the macrolides seems to be directly related to the consumption of specific antimicrobial agent use in the community. Clindamycin resistance is uncommon but does occur. We experienced one case of group A streptoccoccal pneumonia with empyema and pericardial effusion, and treated successfully with amoxicillin-clavulanate, clindamycin and roxithromycin.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.52-60
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• 2005

Purpose : The aim of this study is to know seasonal distribution of group A streptococci obtained from one center using emm genotyping and T serotyping in Masan from 2003 through 2004. Methods : Among children who visited the Changwon Fatima Hospital at Masan, Korea from June 2003 through February 2004, 100 patients who had clinical findings of acute pharyngitis, scarlet fever, and cellulitis were confirmed as GAS by culture, and were enrolled in our study. All obtained GAS were sent to the WHO Collaborative Center for Reference and Research on Streptococci, University of Minnesota, Minneapolis for T serotyping and emm genotyping. We classified these results again according to seasonal and disease's entities. Results : 19 different T serotypes was typed. T4(27.5%), T1(17.6%), T6(13.7%), and T12(13.7%) serotypes were relatively common in summer, while T4(28.3%), T12(15.2%), and T12/B3264(8.7%) were common in winter. T4 and T12 were persistent all year around. Distribution of T serotypes in 89 patients with pharyngotonsillitis were T4(26.7%), T12(14.0%), T1(12.8%), and T6(11.6%) in order of frequency. 15 different emm genotypes was typed. The number of emm 1, emm 6, emm 9, and emm 44 genotypes decreased or disappeared in winter, and the number of emm 3, emm 12, and emm 89 genotypes increased or reappeared in winter. Conclusion : Because T serotyping and emm genotyping are useful tools for evaluating epidemiology and pathogenesis of group A streptococci, we should monitor these strains every year, and should serotype and genotype GAS obtained from the invasive streptococcal infections.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.

• Pediatric Infection and Vaccine
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• v.13 no.2
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• pp.106-114
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• 2006

Purpose : Studying the serotypes and emm genotype of group A streptococci(GAS) hold a key role in the investigation of epidemiology, pathogenesis, and resistance to antibiotics. We planed to find out the possible differences in serotypes and genotypes between the invasive and the non-invasive GAS infection. Methods : We obtained 39 isolates from the patients hospitalized in 2004 with the diagnosis of invasive GAS infectious diseases in the Severance Hospital, Yonsei University. We sent the isolates to the WHO Collaboratory Center in University of Minnesota and analyzed T serotypes and emm genotypes. These results were compared with non-invasive GAS infections in our hospital. Results : Compared this data with the results of 2003 to 2004, T2/28, T3, T5/27/44, T9 and NT were more prevalent. The NT showed statistically significant difference(P=0.019). The emm 3, emm 9, emm 18, emm 44 and emm provision type STG485 were more frequent genotypes compared with the study in 2003~2004, relatively. The emm provision type STG485 had statistically significant difference(P=0.000). The incidence of T12 plus T4, known as erythromycin(EM) resistant serotypes, was as low as 17.9% in this study, compared with those of non-invasive strains. Conclusion : The incidence of EM-resistant strains is supposed not to be higher in invasive GAS infection. We could find out possible higher incidence of rheumatogenic strains in the invasive GAS infections. It seems to be important to have an effort on studying of serotyping and genotyping for the monitoring of strains and to know the epidemiologic characteristics.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.159-165
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• 2004

Purpose: This study aimed to compare the clinical outcome of acute poststreptocaccal glomerulonephritis (APSGN) between patients who had presented with gross hematuria and those with microscopic hematuria. Methods: Thirty-nine patients with acute poststreptococcal glomerulonephritis, who were diagnosed from January 2000 to April 2003 were enrolled. Results: The mean age was 8.85 years and the male to female ratio was 1.1:1 Seventeen patients presented with gross hematuria at diagnosis(group A) and twenty-two patients had microscopic hematuria only(group B). There were no significant differences between the two groups in the incidence of edema, fever or history of respiratory infection and oliguria. But hypertension was more frequent in group B. Laboratory data showed decreased C3 and C4 level in group B. Spot urine protein/creatinine ratio and 24hr urine protein showed higher levels in group A. Conclusion; Patients with gross hematuria at diagnosis had lower incidence of hypertension and a higher rate of nephrotic range of proteinuna than patients with microscopic hematuria. However, no difference in the duration of admission or complication rate was observed. All patients had clinical improvement during follow-up. We conclude that gross hematuria is not a significant prognostic factor for poststreptococcal glomerulonephritis.

• Pediatric Infection and Vaccine
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• v.27 no.2
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• pp.83-89
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• 2020

Purpose: Group A streptococcus (GAS) is a common pathogen in pediatric patients and often causes acute pharyngotonsillitis and skin and soft tissue infections. In addition, bacteremia with significant morbidity and mortality can also occur. This study was conducted to describe the clinical manifestations and treatment outcomes of pediatric GAS bacteremia patients in Korea. Methods: This was a single-center, retrospective study. From January 2000 to December 2016, pediatric patients aged ≤18 years with GAS bacteremia were studied. Clinical manifestations, underlying diseases, intensive care unit stay, and antibiotic susceptibility were evaluated. Results: During the study period, 19 patients had GAS bacteremia. Ten (53%) were male, and the median age was 7.4 years (range, 0.3-17.4 years). Fourteen (74%) had chronic underlying diseases. Five (26%) were immunocompromised (leukemia and chronic kidney disease). Eight (42%) had lymphatic or vascular malformations, of which seven had lesions with signs of inflammation. Three (16%) developed pneumonia, and two of them received ventilator care. The 30-day mortality rate was 6% (1/19), and the cause of death was bacteremic pneumonia. All GAS isolates were sensitive to penicillin. Fifteen (79%) were sensitive to both erythromycin and clindamycin. Conclusions: This study identified various clinical manifestations of GAS bacteremia. GAS should be considered as a potential pathogen that can cause bacteremia and result in a serious clinical course.

• Journal of fish pathology
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• v.19 no.1
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• pp.73-82
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• 2006

Streptococcal infections were considered as a serious problem because of significant economic losses in fish farm industry. We evaluated the efficacies of Streptococcus iniae vaccines in olive flounder, Paralichthys olivaceus. The vaccines were prepared from 10% neutral buffered formalin to give a final concentration of 0.3% or 3%, respectively. Fish were immunized by intraperitoneal injection of the experimental vaccines once or twice. Neither of the vaccines gave rise to any significant side effects. The antibody titers of booster immunized groups were significantly higher than those of prime immunized groups with both of the vaccines. According to formalin dosage, significantly increased antibody titers were produced by 3% formalin-killed cells (FKC) at 4weeks and 8weeks after prime and booster vaccination, respectively. Although the different levels of antibody production were showed by the vaccinated fish, the good protection obtained in challenge trials of the both vaccines. Fish immunized with 0.3% FKC once or twice had the relative percent survival (RPS) of 66.7% and 87.5%, respectively. Similarly, fish immunized with 3% FKC once or twice had the RPS of 70.0% and 77.0%, respectively. Further experiments are needed to study not only correlation between the antibody titers and RPS against S. iniae but also the side effects of high dose of formalin on antigenicity.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.20.1-20.18
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• 2020

Background: Olive flounder, Paralichthys olivaceus, is an economically important aquaculture species in Korea. Olive flounders have been heavily damaged by streptococcal infections every year and are treated with antibiotics. However, antibiotic abuse is causing the emergence of resistant strains, and to overcome this, research has shown that new antibiotics must be applied. Tylosin is a relatively safe antibiotic and has good activity against Gram-positive bacteria and mycoplasma. We studied the therapeutic effects and side effects of tylosin on Streptococcus parauberis-infected olive flounder. Methods: After artificial infection of olive flounder with S. parauberis SPOF18J3, an appropriate dose of tylosin was confirmed by intramuscular injection (I.M.) at 2.5, 5, 10, and 15 mg/kg, and oral administration at 10 and 20 mg/kg. After I.M. and oral administration dosing of tylosin, side effects were confirmed by serological analysis, histopathological analysis, and median lethal dose (LD₅₀) analysis at both an appropriate concentration and a high concentration. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey's test (p < 0.05). Results: The appropriate I.M. and oral administration concentration of tylosin administered to olive flounder infected with S. parauberis SPOF18J3 was found to be 10 mg/kg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were showed not significantly different between the control group and the experimental groups. The histopathologic results showed mild inflammatory responses in muscle and tubular vacuolization and tubular atrophy appeared, but there were no significant differences between the groups. The LD₅₀ was confirmed to be 461 mg/kg. Conclusion: In this study, an effective treatment method was provided by verifying the treatment effects and side effects of tylosin in olive flounder infected with S. parauberis, which can be applied directly to aquaculture sites. In addition, these results may be used as a reference for evaluation required upon request to obtain approval for tylosin antibiotics as fishery antibiotics in Korea. After approval, it is possible that a fishery disease manager will be able to prescribe and sell the antibiotic tylosin.

• The Journal of the Korean Society for Microbiology
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• v.35 no.2
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• pp.171-180
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• 2000

Ninety two strains of Streptococcus pyogenes were isolated from patients with pharyngitis, scarlet fever, skin infection, and invasive streptococcal infections in Seoul, Korea from January to December, 1998. All isolates were epidemiologically characterized by T protein serotype, and serum opacity factor (OF) detection to phenotypes. To analyze the genetic relationship, fifty two isolates including 32 erythromycin-clindamycin (Em-Cm) resistant strains, 20 antimicrobial susceptible strains were attempted to the pulsed-field gel electrophoresis (PFGE). T protein serotype showed 16 kinds in distribution including T12 and T4. Among the total isolates, 40 strains (43.5%) belonged to the T12 serotype and twenty strains (21.7%) to T4 serotype. On the other hand, when infection aspect of S. pyogenes isolates were analysed by T serotype distribution, T12 type was predominant for pharyngitidis which contributed to 21 strains (53%) and for skin infection isolates which contributed to 11 strains (28%), respectively. In case of T4 type, it was the most predominant pharyngitidis isolates which contributed to 8 strains (40%). In T serotype distribution of Em-Cm resistant strains, 27 strains (84%) of the thirty two showed T12 serotype. In minimum inhibitory concentration (MIC) values of Em-Cm resistance isolates, thirty two isolates showed resistant to erythromycin 27 strains (84%), had high MIC of >$128\;{\mu}g/ml$. And also to clindamycin, twenty two strains (69%) had high MIC of >$128\;{\mu}g/ml$. When OF detection of Em-Cm resistance of S. pyogenes isolates were analyzed by T serotype distribution, T12 serotype isolates revealed that all of the isolates except one strain were OF negative. In PFGE profile analysis to Em-Cm resistance isolates, of the twenty seven, Em-Cm resistance of T12 serotype isolates, 26 strains showed identical PFGE profile and all of these isolates revealed that OF negative. Eighty four percent of Em-Cm resistance S. pyogenes isolates had identical phenotype and PFGE profile. These results strongly suggested that the Em-Cm resistant S. pyogenes isolates from Seoul area showed close genetic correlation and PFGE could be available tool for molecular epidemiology.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.79-86
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• 2017

Purpose: This study was aimed at analyzing the serotypes of group B streptococcus (GBS) isolated from Korean infants with invasive disease and evaluating their association with disease manifestation. Methods: Data were retrospectively collected from invasive GBS infections at Gachon University Gil Medical Center from January 2006 to June 2012 and at Samsung Medical Center from April 2010 to November 2012. Serotypes were determined by slide agglutination test. Results: A total of 37 cases were identified, which included 22 full-term infants and 15 preterm infants. Fifteen cases (40.5%) were early-onset, 19 (51.4%) was late-onset, and three (8.1%) was very late-onset. Early-onset diseases among preterm infants were higher than those among full-term infants (60.0% [9/15] vs. 27.3% [6/22], P=0.17). The most common manifestation was bacteremia (70.3%), followed by meningitis and septic arthritis. Among 24 isolates retrievable for serotyping, serotype III (41.7%) was most common, followed by V (16.7%), Ia, Ib, and II (12.5%, respectively), and non-typeable (4.2%). Serotype III was more common in isolates from full-term infants (10/22) than from preterm infants (0/15), whereas serotype V was more common in isolates from preterm infants (4/15) than from full-term infants (0/22) (P=0.002). No penicillin-resistant strain was detected, and resistance to erythromycin and clindamycin were both 64.9%. Conclusions: GBS is an important pathogen in both preterm and full-term infants, and serotype distribution of GBS causing invasive diseases can differ between preterm and full-term infants. It is necessary to monitor the nationwide epidemiology of GBS diseases, including in preterm infants, in order to prepare preventive measures without underestimating early-onset diseases.